This invention relates to atomic absorption photometers and more particularly to atomic absorption flame photometers which use a flame generated by burning a gas to atomize a sample.
Such an atomic absorption flame photometer typically uses a burner to subject a sample to a burning process by generating a flame above a slot provided to a burner head. A mixture of a combustion gas and a combustion improving gas is usually burnt together to generate a flame. Examples of combustion gas include acetylene (C.sub.2 H.sub.2), and examples of combustion improving gas include air and N.sub.2 O. An atomic absorption flame photometer is usually provided with a safety device for monitoring whether the burning of the flame is proceeding safely or not. Examples of such a device include gas pressure monitors.
Gas pressure monitors are for monitoring the pressure of the gas which is being supplied so as either to prevent the use of a flame if the gas pressure becomes low or to automatically shut off the supply of gas in the midst of a combustion process and to extinguish the flame safely.
If such a monitor malfunctions, and in particular if the malfunctioning is such that the monitor would regard an unsafe condition as being safe, the situation is very serious because the safety device is not functioning as such. The cause of a malfunctioning may be electrical in nature such as a broken cable or an imperfect connection by a connector. In the case of a gas pressure monitor, it may be due to a mobile part of the pressure switch getting stuck somewhere.
Prior art attempts at preventing accidents due to such malfunctions included using a more reliable and hence more expensive monitor and using two or more sensors. All these methods were costly, causing an increase in the production cost of the monitor.